Electric terminal



C. C. ABBOTT.

ELECTRIC TERMINAL.

APPLICATION FILED Aue,2s,1921.

1,432,435. Patented Oct. 17, 1922.

Fig.2.

Inventor C haries 0. Abbott,

Patented Oct. 17, 1922.

UNITED STATES PATENT OFFICE.

. CHARLES C. ABBOTT, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

. ELECTRIC TERMINAL.

Application filed August 23, 1921. Serial NO. 494,652.

To all whom it may concern:

Be it known that I, CHARLns C. Anno'r'r, a citizen of the llnited States, residin at Pittsfield, in the county of Berkshire, tate of Massachusetts, have invented certain new and useful lmprovements in Electric Terminals, of which the following is a specification.

My invention relates to improvements in terminal arrangements for electric conductors and has for its object the provision of simple, reliable and. economical means for making electric connections.

More specifically, my invention relates to the connection of terminals for heating units of the type described and claimed in my copending application, Serial No. 294,837, filed May 3, 1919, assigned to the same assignee as this invention, although it has application to various types of electrical apparatus.

In carrying out my invention l provide a longitudinal hole in the terminal and an intersecting transverse hole therein. The metallic conducting lead for the resistance element is inserted in the longitudinal hole, and then the terminal is swaged. The swaging operation reduces the diameter of the terminal and likewise the diameters of the longitudinal hole and the portions of the lead in engagementwith the walls of the hole. The result is that portions of the lead are forced into the transverse hole at the intersection so as. to hold the lead firmly in place. I have also provided a connection between the terminal and the resistance element which consists in passing the end of the resistance element through a transverse hole in the terminal and winding it up on a tapered recess on the terminal so that it is wedged tightly between the terminal and the insulating support in whlch the terminal is seated.

In the accompanying drawing, Fig. 1 1s a View partially in section showing the attachment of terminals in accordance with my invention; Fig. 2 is an enlarged sectional View of the terminal before the swaging operation; Fig. 3 is an enlarged view partially in section of the terminal showing the conducting lead secured thereto; Fig. iis an end elevation view of the terminal showing the squared portion; Fig. 5 is a section view along the line 5-5 of Fig. 1 looking in the direction of the arrows, while Fig. 6 is asection view along the line 61-6 of Fig. 1 look- 111%{111 the direction of the arrows. D eferring to Figs. 1, 5 and 6 of the drawmg, the heating unit 10 is provided with a cylindrical core 11 of suitable insulating material such as lava, for supporting the resistance wire 12 and the metallic terminals 13 and 14:. The terminals 13 and 1% are inserted in parallel longitudinal holes 13' and 14c in the core, while the resistance wire 12 is wound on the core. To facilitate the attachment of the resistance wire to the terminals, a narrow longitudinal slot 15 intersecting with longitudinal hole 13 is provided in the insulating core. This slot extends the full l en h of the core and also across the left hand end of the core. A small transverse hole 16 extends into longitudinal hole 14 in the core. The terminals 13 and 14 are provided with projecting leads 1'? of suitable conducting material which may be either solid or stranded.

eferring to Fig. 2 of the drawing, the terminal 13 consists of a cylindrical piece of suitable electrically conducting material having a short length 22 at the left hand end reduced in diameter and a tapered pe-' ripheral recess 22 near the right hand end. In the right hand end of the terminal are drilled a longitudinal hole 18 slightly larger than the lead 17 and a transverse hole 19 intersecting therewith. The lead 17 is then inserted in the hole 18, and the terminal subjected to a swaging process whereby the diameterof the body of the terminal, not including length 22' and the tapered portion at recess 22, is reduced, as shown in Fig. 3. It will be observed that during the swaging operation, the hole 18 is reduced in diameter and as a result the diameters of the portions of the lead inengagement with the walls of the hole are reduced. The portion 20 of the lead registering with transverse hole 19 is flattened but not reduced in size, however, so that an enlarged flattened portion 20 is formed on the lead around which the walls of the longitudinal hole are tightly swaged. This enlarged portion has projections extending from. opposite sides of the lead which are forced into the transverse hole 19 so as to hold the lead securely in place against both longitudinal and turning movement and in electrically conducting relation with the terminal. The swaging operation produces a reliable and permanent electrical means oi dies.

lea

such connection between the terminal and the The maximum depth of the recess 22 the swaging operation is equal to the diameter of the resistance wire to be used.

A transverse hole 521 is now drilled through the terminal the point of greatest depth of recess 2%, and the length 22 squared by The diameter of portion 2.2 is such that'when squared its section has a diagonal dimension equal to the. diameter of the body of the terminal, as shown in Fig. i

Tn the assembly oif a heating ,unit of the disclosed in F i i, the terminals 13 e. constructed as described in connecwith Figs. 2 and 3 are inserted squared innermost in the longitudinal holes 13" and-la in the core ll, the holes being oi depth that the terminals project slightly. @ne end of the resistance wire 12 is then passed through hole 21 in the terminal l3 and the terminal turned so as to wind the resistance wire in the recess. Alter one complete the resistance V h I till wire winds up on the tapered recess until the hole in the core member is tilled and the resistance wire secured tightly in good electrical contact with the terminal between the terminal and the core member. The terminal is also secured to the core member at The resistance wire is then laid groove 15 along the length across the lelt end of the core member. lln the n t step the resistance wire is wound on the core member, suitable insulating space leit between turns, and cut to leave free end of the required length, which is passed through the hole 16 in the core member and inserted in the hole 21 in terminal i l, the hole 21 having been aligned with hole 16. with relation to the'core member so as to wind the resistance wire in the recess until a tight connection is made? as described in connection terminal 13, all slack in the resistance wire being talren up at the same time. Tn case a resistance wire of relatively small diameter is used, the tapered recess in the terminal may not be necessary. The core member with the resistance wire and terminals secured thereto is then placed in the cylindrical casing .23, and powdered heat refractory insulating material 2t, such as magnesium oxide, packed between the core member and the casing and around the resistance wire. .7 The end or the casing is closed by a. suitable insulating disc 25 through openings in which the leads 1? extend and by 'a metallic disc 26 having en-,

larged openings around the leads for insulation therefrom. The walls or the casing are next turned over so as to hold the metallic ,disc in place. The entire unit is then subjected to a swagingprocess whereby the powdered insulating material is compacted Terminal 1 lis then turned application. The swaging operation causes the core member to collapse and flow somewhat and thus compresses it tightly around the terminals so as to secure the terminals against turning movement with relation to the core member by reason of their squared ends.

lit will be observed that by means at my invention the terminals are connected to the resistance wire and the leads in every sireple, reliable and economical manner and without the use of brazed joints. The termin-a1 can be inspected through the transverse hole to determine whether the lead is properly in place during the swaging operation. Obviously, my invention has appli cation to various types of heating units other than the specific type described herein.

Tn" accordance with the provisionsoi the patent statutes, l have described the principle of operation of my inventiom'together with the apparatus which ll now consider to represent the best embodiment thereof, but It desire to have it understoodthat the apparatus shown is only illustrative and that the invention can be carried; out by other means.

W hat ll claim as new and desire to secure by Letters Patent of the United States, 152- 1. The method of securing a terminal to an electric conductor which consists in iTOIl'llminal until an enlarged.portion-extending into said transverse *hole at the intersection is termed on the conductor to lock it in place. i

3. A terminal for electric conductors 1 comprising a terminal member recessed to receive the conductor, and provided with an intersecting recess into which the conductor is forced to lock it in place. i

l. A terminal for comprising a terminal memberrecessed to receive the. conductor and provided with an electric conductors Mill intersecting recess into which the conductor is forced to lock it in place by reducing the.

cross section of the terminal.

' 51. A terminal for electric, conductors comprising a terminal member provided with a lon 'tudinal recess to receive the conductor, an an intersecting recess intowhich the conductor is caused to extend to lock it in place by reducing the diameter of the terminal by swaging.

6. The combination with an insulating support of a terminal arranged to be inserted therein, comprising a terminal member provided with a tapered portion on which the resistance Wire is Wound until it is support of a terminal arranged to be inserted therein, comprising a terminal member provided with a tapered portion having a transverse aperture into which the resistance Wire is inserted and Wound up on the tapered portion by turning the terminal until it is wedged between the terminal and the insulating support.

locked between the terminal and the insulat- 10 ing support.

my hand this 20th day of Au 1921. 7. The combination With an insulating CHARLES ABBOTT.

In Witness whereof, I have hereunto set 20 

